1. Field of the Invention
This invention relates to blends of acrylate-styrene-acrylonitrile interpolymers (ASA resins) with a particular acrylate resin for gloss reduction.
2. Description of the Prior Art
Molded products made of thermoplastic resins are frequently glossy. For some purposes, this is desirable. However, a matte or non-glossy surface is often preferable for products such as housings for computer terminals, typewriters, miscellaneous electrical appliances and certain automotive parts. There is substantial commercial need for molding resin compositions which are non-glossy.
Elimination of gloss by surface embossing has been practiced but requires a separate step and adds cost, Moreover, subsequent abrasion may remove the embossed matte surface and cause the gloss to reappear. The addition of a delustering agent such as finely-divided silica, silicate, alumina, or other mineral filler has a seriously detrimental effect on the physical properties of the molded object, such as impact strength. Attempts to add a polymeric delustering agent frequently also have deleterious effects on physical properties, not only on impact strength but also on heat distortion temperature, weld line strength, weathering, light stability, and other important properties. The reduction of gloss in certain specified thermoplastic blends by adding a copolymer crosslinked by means of allyl functionality has been described in U.S. Pat. No. 4,460,742.
Acrylonitrile-styrene-acrylate interpolymers (ASA resins) are well known in the art, and have many favorable features such as good strength and outstanding weathering resistance. However, such resins tend to have glossy characteristics, and the same disadvantages as discussed above are observed when conventional methods of reducing gloss are applied to these resins. It is desired to have a means for reducing the gloss in resins predominantly consisting of ASA, while maintaining good physical properties such as strength and weathering resistance.